Ranking of Steels in Categories based on Edge Retention cutting 5/8" rope

Ballenxj said:
Hi Jim, Thanks for taking the time to do this testing, and posting your results.
A quick question; I note that your results for S30V ended up in two different categories.
Category 3, and I'm assuming the Rockwell hardness is in parenthesis, of (60)?
Again I find S30V in category 5, with a Rockwell hardness of (58.5)?
Did I miss something, or is this just the way the testing worked out with two separate examples?
Thanks. :)
-Bruce
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RC hardness will make a huge difference in performance.

S30V at 58.5 RC and 60 RC is like testing 2 different steels, blades were the same shape, grind, edge profile etc.
 
Ankerson said:
RC hardness will make a huge difference in performance.

S30V at 58.5 RC and 60 RC is like testing 2 different steels, blades were the same shape, grind, edge profile etc.
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And this was my point. I know S30V is a blend of powdered steel, etc. but shouldn't the test results be more consistent if both steels were supposed to be the same? :confused:
-Bruce
 
Ballenxj said:
And this was my point. I know S30V is a blend of powdered steel, etc. but shouldn't the test results be more consistent if both steels were supposed to be the same? :confused:
-Bruce
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No, Rockwell Hardness has a huge impact on performance.
 
Ankerson said:
No, Rockwell Hardness has a huge impact on performance.
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I see. So, even if the steels are the same, the temper may vary? I would have thought they would be tempered the same?
BTW, I'm just asking these questions in the hopes of learning something here. Well, that, and I own a Benchmade DejaVoo that is made from S30V, and I believe is Rockwell rated at 60. ;)
-Bruce
 
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Ballenxj said:
I see. So, even if the steels are the same, the temper may vary? I would have thought they would be tempered the same?
BTW, I'm just asking these questions in the hopes of learning something here. Well, that, and I own a Benchmade Deja' Voo that is made from S30V, and I believe is Rockwell rated at 60. ;)
-Bruce
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Tempering is part of the HT process, Rockwell Hardness is different.

We never know what hardness the blades are until they are tested.
 
Ballenxj said:
And this was my point. I know S30V is a blend of powdered steel, etc. but shouldn't the test results be more consistent if both steels were supposed to be the same? :confused:
-Bruce
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Not really no. After looking at some of the Crucible datasheets, I noticed that corrosion resistance, toughness, and wear resistance are different at different hardness levels. Which means that the heat treat can control the carbide volume and amount of free chromium in the matrix.

As someone mentioned before, the "old" 1095 carbon steel with a good heat treat can outperform the modern S30V steel with a botched heat treat.
 
Ankerson said:
Tempering is part of the HT process, Rockwell Hardness is different.

We never know what hardness the blades are until they are tested.
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Just looked the DejaVoo up on Benchmades site. They rate the S30V steel on that knife at 58-60. Is this about as much variation that is to be expected, or can there be more? Are they just taking an average?
-Bruce
 
noctis makes a good point seldom mentioned. heattreats in addition to making blades have different rockwells also make microscopic structural differences. i wish some of the mettalurgists would kick in but as most engineers i know they work so much that they have little time to make contributions. i know engineers whom stay on their laptops hooked in to the company main system while the wives are driving to locations for the vacation. ballenxj i know that my millie used in the tests was a 58 r.r. most spydies in s30 run about 60 r.r.i read that within the same alloy 2 points r.r. can mean up to 20% increase of edge durability.my blade was a blackened blade & it's been conjectured the coating process uses enough heat to affect r.r.whether this is a fact i do'nt know but i imagine we will hear more on this in future.for myself i will purchase uncoated blades in the future.--dennis
 
DennisStrickland said:
ballenxj i know that my millie used in the tests was a 58 r.r. most spydies in s30 run about 60 r.r.i read that within the same alloy 2 points r.r. can mean up to 20% increase of edge durability.my blade was a blackened blade & it's been conjectured the coating process uses enough heat to affect r.r.whether this is a fact i do'nt know but i imagine we will hear more on this in future.for myself i will purchase uncoated blades in the future.--dennis
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Thanks Dennis, Interesting to know that 2 points can change edge durability by up to 20%.
RE; Blade coating. It makes sense that if coating a blade requires heat, it could affect the temper of the steel. I'm glad my preference is for non coated blades. ;)
-Bruce
 
ballenxj i'm no mettalurgist that info is some thing i read but tests by knarfeng & ankerson seem to indicate this may be fairly correct on the info about rockwell as related to edge endurance.
dennis
 
Nice! I'm going to have to get both some white and blue to compare to the super blue.
 
What knife did you test the Elmax on? Also, I assume you used the Spyderco Mule for the Super Blue? Is that correct?
 
How do the edges look & feel when they reach 20 lbs? Are they getting evenly smoothed over, microchipping, denting/rolling, etc?
 
hardheart said:
How do the edges look & feel when they reach 20 lbs? Are they getting evenly smoothed over, microchipping, denting/rolling, etc?
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Most will still slice Newspaper, but yeah they have lost most their bite for sure. They feel smooth, but will still grab my fingernail.

I have seen some edge damage on some of the steels, shiny spots and a little chipping depending on the steel.

Manila rope is very hard on edges.
 
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